Faced with a situation where an old but beloved one refrigerator stops freezing, many owners are thinking about writing it off. However, if the compressor is humming, but it’s warm inside, the problem most often lies in a banal leak refrigerant. Restoring the functionality of the unit in this case requires a complete recharge of the system.
This process is technically complex and requires special tools, but theoretical knowledge will help you assess the scale of the disaster or even carry out repairs yourself if you have the skills to work with metal. It is important to understand that you cannot simply “add gas” - the system must be sealed and evacuated.
In this article we will analyze all the stages: from finding a leak to the final start. compressor. You will learn about the types of freon, the necessary tools and safety measures that cannot be ignored under any circumstances.
Leak diagnostics and equipment preparation
Before you start refilling, you need to make sure that there are no holes in the system. If refrigerant gone, it means he came out through the hole. Refilling without fixing the leak is money down the drain. First of all, carefully inspect all accessible pipes, especially the soldering points and connections with the compressor.
To search for micro-leaks, professionals use nitrogen under pressure, but at home they often use a soap solution. Apply thick foam to suspicious areas. The appearance of bubbles will indicate the location of depressurization. It is also worth paying attention to the presence of oily stains around the tubes, since freon often comes out along with the oil.
⚠️ Attention: If you find a leak in the foamed part of the housing (the evaporator inside the cabinet), independent repair may be impractical due to the difficulty of accessing the tubes.
To carry out the work, you will need a specialized set of tools. Without them, quality work vacuuming and refueling will not work. The basic kit includes a pressure gauge station, a vacuum pump and a refrigerant cylinder.
Necessary tools and materials
The quality of the work directly depends on the equipment used. The use of homemade devices or automobile pumps to create a vacuum is unacceptable, since they cannot provide the required degree of vacuum in the system.
You will need gauge manifold, which allows you to control the pressure during evacuation and refueling. Also an indispensable tool is a torch for soldering copper tubes, preferably using hard solder (PSR) and flux.
- 🔧 Gauge station with hoses of different colors to separate circuits.
- 🌬️ Vacuum pump for removing air and moisture from the system.
- 🧪 Freon cylinder (the brand depends on the model of your refrigerator).
- 🔥 Gas burner and solder for sealing connections.
Special attention should be paid to the choice solder. For copper tubes of refrigerators, silver solder or special rods containing silver are best suited, which provide high weld strength and resistance to vibration.
Choice suitable refrigerant
Old refrigerators can operate on different types of refrigerants. Most often, Soviet and post-Soviet technology used R12 (dichlorodifluoromethane), which is now banned for production due to its harmful effect on the ozone layer, but is still sold for repairs.
More modern models, even 15-20 years old, can be filled with freon. R134a. These gases are not directly interchangeable. Using the wrong freon will either result in a lack of cold or compressor failure due to overheating or mismatch of oil properties.
| Freon type | Chemical formula | System pressure | Compatibility oils |
|---|---|---|---|
| R12 | CCl2F2 | Low | Mineral |
| R134a | CH2FCF3 | Medium | Synthetic (POE) |
| R600a | C4H10 | Low | Mineral |
| R404a | Blend | High | Synthetic |
To find out what kind of gas was used in your unit, look at the nameplate, usually located inside the chamber or on the back wall. The exact brand and weight of the refill is indicated there.
Is it possible to replace R12 with R134a?
Theoretically it is possible, but this requires a complete replacement of the oil in the compressor with synthetic and thorough flushing of the system. A simple replacement without flushing will lead to the formation of an acidic environment and rapid combustion of the motor.
The process of evacuation of the system
After eliminating all leaks and replacing the filter-drier (which is a mandatory procedure when opening the circuit), it is necessary to remove air and moisture from the system. Moisture is the main enemy of the refrigerator; it freezes in the capillary and causes an ice jam.
Connect the vacuum pump to the service fitting. Turn on the pump and monitor the pressure gauge. The arrow should drop below zero, indicating a deep vacuum. The process should last at least 30-40 minutes to ensure the removal of water vapor.
⚠️ Attention: Never turn on the compressor for “self-evacuation”. This leads to combustion of the windings and decomposition of the oil, since the motor is not designed to operate in a vacuum without gas flow.
When the process is completed, first close the valve on the pressure gauge, and only then turn off the pump. This will prevent oil from flowing back from the pump into the refrigerator system.
☑️ Checklist before refueling
Freon charging technology
The most accurate method refills - by weight. The nameplate always indicates the mass of the refrigerant in grams. You will need electronic scales on which you place a cylinder of freon. By opening the valve, you control the decrease in gas mass.
If there are no scales, you can use the pressure and current consumption of the compressor as a guide, but this method requires experience. For R12 the working suction pressure is about 0.05-0.08 MPa, for R134a it is slightly higher. However, the pressure strongly depends on the ambient temperature.
When refueling, you need to start the compressor briefly, creating a vacuum in the operating system in order to draw in the required amount of gas. After gaining weight, the cylinder is closed, the hose is disconnected and the fitting is sealed.
Checking performance and typical errors
After refueling, turn on the refrigerator and let it run for at least an hour. Check the heating of the condenser (grid at the back) - it should be warm evenly along its entire length. The evaporator inside the chamber should be covered with frost or “cry.”
A common mistake is to ignore replacing the filter-drier. The old sorbent is already saturated with moisture and will not be able to clean the new freon, which will quickly lead to blockage of the capillary tube.
- ❌ Refilling “by eye” without a pressure gauge often leads to an excess of gas.
- ❌ The use of automotive sealants to eliminate leaks in the refrigerator is unacceptable.
- ❌ Soldering without nitrogen purge (if possible) can create oxides inside the tubes.
If after refueling the refrigerator works, but does not cool well, there may be air or moisture left in the system. In this case, the evacuation and refueling procedure will have to be repeated.
What to do if the compressor inlet tube freezes after refueling?
This is a sure sign that there is an excess of freon in the system or the filter drier is clogged. It is necessary to bleed off some of the gas through the piercing device or replace the filter if refueling was carried out strictly according to the norm.
Is it possible to use freon from a car air conditioner?
Absolutely not. Automotive freons often contain additives of dyes and phosphors to detect leaks, and may also have a different chemical base, which will kill the refrigerator.
How can you tell that the compressor has burned out?
If you hear a relay click when you turn it on, the buzz lasts 2-3 seconds and there is a click again, and then silence - most likely it is jammed compressor or winding burnt out. Refilling with freon will not help here.